Turbo-coredrill for ground drilling



P 25, 1962 w. TIRASPOLSKY ETAL 3,055,440

TURBOCOREDRILL FOR GROUND DRILLING Filed Oct. 27, 1958 2 Sheets-Sheet 1Sept. 25, 1962 w. TIRASPOLSKY EI'AL 3,055,440

TURBO-COREDRILL FOR GROUND DRILLING Filed Oct. 27, 1958 2 Sheets-Sheet 2United States Patent TURBO-COREDRILL FOR GROUND DRILLING WladirnirTiraspolsky, Issy-les-Moulineaux, and Roger Francois Rouviere,Aureilhan, France, assignors to Turbodrill International Corporation,Schaan, Liechtenstein Filed Oct. 27, 1958, Ser. No. 769,702 Claimspriority, application France Oct. 28, 1957 7 Claims. (Cl. 175--107) Thepresent invention relates generally to coredrills as utilized whendrilling the ground for bringing up to the earth surface cores orsamples of those layers of ground through which the drilling operationis performed.

Turbo-coredrills as manufactured and used hitherto and more generallycoredrills actuated by a subterranean motor comprise a rotary hollowshaft through which a retractable inner core tube is engaged, said coretube resting upon an annular seat provided over the top end of saidshaft and operatively connected to the stator structure of the motor.The tubes adapted to collect the cores are usually provided with afishing head which allows to bring them up by means of a specialgripping tool (overshot) which is lowered inside the rods and isfastened to the end of an operating cable.

An annular space should accordingly be provided between the rotary shaftof the motor and the inner core tube. If the radial size of said annularspace is too small, a friction takes place between the shaft and theinner core tube, which may either damage said tube or impart a rotarybias thereto. Where, conversely, said annular space is too wide, anappreciable portion of the operative fluid then flows through theresultant channel.

The fluid stream which is derived owing to this phenomenon is subtractedfrom the working steam of the turbine and maintains in the aforesaidannular space unduly high pressures which may hinder proper outflow ofthe fluid at the upper end of the inner core tube as the core graduallypenetrates into it. Now the efficiency of a coredrill (expressed inpercentage of the recovered core) is among other factors subordinated tothe possibility of doing away with any substantial over pressure insidethe inner core tube which is usually fitted with a relief valve. Whereaccordingly high pressures prevail inside the aforesaid annular space,this has the effect of diminishing the length of the core that can beobtained in each run. In turbo-coredrills as used at present the maximumcore length is generally smaller than about fifty percent of the totallen th of the core tube.

An object of the invention is to remedy the disadvantage above referredto of coredrills as at present in use and to provide a novel or improvedcoredrill capable of furnishing, when properly used, cores of greaterlength than present coredrills owing to a better coring efficiency.

Another object of the invention is to provide a turbocoredrill ofimproved structure comprising a retractable inner core tube adapted tobe replaced in the course of the drilling operation without any need forthe rods to be raised out of the well being bored and characterized bythe provision at the upper end of the inner core tube and/ or theturbine shaft of a device which obturates the annular space definedbetween the inner core tube and the hollow shaft of the turbine so as toprevent the fluid from flowing through said annular space or to limitthe fluid flow to that minimum value which is necessary for lubricatingthe device.

A further object of the invention is to provide a turbocoredrill asaforesaid wherein the above-cited device is so built as to form anabutment or bearing carrying the inner core tube which thus restsaxially on the head of the hollow turbine shaft instead of being axiallymaintained in the usual fashion on a seat formed in the stator, thisconstruction permitting to avoid axial movements of the lower end of theinner core tube with respect to the rock, said movements beingunavoidable with a coredrill of usual construction on account of therelative axial hunting motion which takes place between the stator andthe rotor within the boundaries of permissible axial clearances which,as is known, do not represent a constant value but a value whichincreases as the thrust bearings gradually become worn off.

A still further object of the invention is to provide an improvedturbo-coredrill as aforesaid wherein the obturating device may beoperatively combined with an additional device locking the inner coretube in a fixed angular position relatively to the stator so that theinner core tube may not rotate while coring occurs.

The position of the cores with respect to the stator is thus fixed andif desired means are therefore available for taking spatially orientatedcores.

It will be understood that while throughout the specification referenceis made to turbo-coredrills i.e. to the application of the invention toturbines for drilling the ground particularly for the exploitation ofoil fields, the invention is applicable in a more general way to anytype of underground or subterranean motor or prime mover used for coringand particularly to electric motors.

It will be also understood that the device for angularly setting theinner core tube may be also used for angularly setting the dip-measuringapparatus which may, at the end of a coring phase or at any desiredtime, be substituted for the inner core tube, thereby permitting thestator to be angularly set or orientated with respect to the azimuth ofthe bore hole dip as soon as said hole shows a measurable degree ofdeviation.

With the foregoing and such other objects in view as will incidentallyappear hereafter, the invention comprises the novel construction andcombination of parts that will be now described with reference to theaccompanying diagrammatic drawings exemplifying the same and forming apart of the present disclosure.

In the drawings:

FIGURE 1 is a partial vertical sectional view of an improvedturbo-coredrill according to the invention.

FIGURE 2 is a view similar to FIG. 1 showing a constructionalmodification.

FIGURE 3 is a perspective view partly broken away of a constructionaldetail.

In the showing of FIG. 1, the tubular casing body member portion 1 ofthe turbo-coredrill terminates at its upper end in a joint or union 2which provides a lower shoulder against which the upper part or element3 of the stator part stack is abutted. A left-handed thread 4 of thejoint 2 receives the seat 5 of the inner core tube which is screwed intoit and is thus rigidly connected relative to the stator. The seat 5 hasa central conical crown member 6 and peripheral circulation channels 7.

The revoluble shaft 8 of the turbo-coredrill is rigid with the stack ofrotor parts. For the sake of clearer illustration, only the upper locknut 9 of said rotor stack and the upper part 3 of the stator have beenshown. The shaft 8 is hollow and permits free passage therethrough ofthe inner core tube 10 whose top joint is indicated by 11. Said joint isprovided with spanner-receiving notches 12 and is screwed at its top endinto the head 13 of the inner core tube 10 which is provided likewisewith spanner-receiving notches 14. Said head sits upon its lower conicalbearing surface 15 upon the conical abutment surface of the inner crownmember 6 of the seat 5.

According to the invention, a sleeve-shaped rotary sealing device 16fitted internally with rubber or like gaskets 17 adapted to be appliedagainst the outer face of the upper joint 11 of the inner core tube isinterposed between said sealing device and the rotary hollow shaft 8.Said joint is held in position by a top shoulder nut 18 which providesin cooperation with the upper part of shaft 8 an annular recess in whichis received a conical ring member 19 which ensures a sealing effect andrests along a supple coating 20 (made for example of rubber) against theconical seat formed (as shown) at the top end of the rotary shaft 8. Acertain amount of clearance is provided as shown at 21 between saidconical ring member and the sealing device 16 so as to allow said ringmember to move radially with respect to the sealing device 16 and to thenut 18, thereby eventually compensating for the eccentricity of theshaft 8 with respect to the seat 5.

The upper joint 11 of the inner core tube has a shoulder 22 which actsas an abutment surface for the rotary sealing device when extracting thecore tube 10. There is provided at the lower end of the joint 11 athread for securing a valve seat 23 against which a valve ball 24 isnormally applied by a spring 25, the fluid escaping through a vent 26.

During operation, the head of the inner core tube 10 rests against theinner crown member 6 of the seat 5 to which it is applied owing to thedifference of pressure which prevails between the inlet and the outletof the turblue. The rotary sealing device 16 rests in turn against theconical bearing provided on the shaft 8 and is pressed against saidshaft by the aforesaid pressure difference. As the sealing device 16 isrevolubly driven by the rotating shaft 8, it rotates about the upperjoint 11 of the inner core tube 10. Rotation is facilitated by thegaskets or bearing lines 17. Thus said sealing device seals off theannular gap defined between the inner core tube and the shaft, but thegaskets or bearing liners 17 obviously allow a reduced flow of liquidfor lubricating said gaskets in a well-known manner.

According to the constructional modification which is shown in FIG. 2 inwhich the head of the inner core tube rests on the shaft head whilebeing angularly held in a stator seat, the body 28 of theturbo-coredrill carries a top joint 29 forming an abutment for the upperend 30 of the stator stack. A threaded portion on the joint 29 permitsthe guiding seat 31 of the inner core tube to be mounted thereon, saidguiding seat including (see FIG. 3) channels 32 for the fluid flow, ribs33, a crown member 34 and a helical ramp 35 the upper and lower outsetsof which are visible in FIG. 3, while the end portions of said rampdefine a vertical key slot 36. In this slot 36 is normally received asingle key rib 37 which projects from the periphery of the head 38 ofthe inner core tube which is provided with spanner-receiving notches 39and is surmounted by a so-called fishing mushroom 40. The head 38 isprovided adjacent its lower end with a conical bearing surface having ananti-abrasive coating 41. The upper joint 42 of the inner core tube isscrewed through an inner thread 43 in the head 38, said joint 42 havingdriving flutes 44 the purpose of which is indicated hereafter. Thereference numeral '45 designates the vent of the inner core tube valve,while the reference numeral 46 designates the upper shoulder on saidtube.

The revoluble shaft 47 of the turbo-coredrill is fitted adjacent itsupper end with a bearing or abutment joint 48 for mounting rubberbearing seats 49 and spacer sleeves 50, the assembly being clamped by alocking nut 51. The rubber seats 49 cooperate with wear-taking discs 52which are mounted with spacer sleeves 53 on a stationary bearing body 54having a lower threaded portion 55 on which is screwed abearing-carrying nut 56. Said bearing body 54 is sleeve shaped andprovides together with the discs 49, 52 an annular, substantiallysleeve-shaped sealing device between shaft 47 and the inner core tube42. Said body 54 is fitted on its inner periphery with longitudinallyextending flutes 57 matching the flutes 44 in the upper joint 42 of theinner core tube.

The operation of the device is as follows: When the device occupies itsnormal working position, the coating 41 provided on the head 38 of theinner core tube rests upon the conical bearing surface 58 of the bearingbody 54 and provides a sealing effect. The gap defined between the innercore tube and the rotary hollow shaft 47 is obturated in the presentcase both by the head bearing and by the bearing body 54 acting as asealing device. Consequently only the portion of fluid which isnecessary for irrigating the bearings 49 and 52 is allowed to flowbetween the bearing body 54 and the locking nut 51. In such normalposition, the inner core tube is angularly locked with respect to thebody of the coredrill and to the stator, said angular locking beingobtained in the following manner as the inner core tube is positioned:

As the inner core tube is lowered by a free fall through the hollow rodsand as said tube reaches the turbo-coredrill, the rib 37 rests upon theramp 35 and the part 31 which is rigid with the stator, said twoelements being so treated as to resist mechanical strains resulting fromsaid contact. When this occurs, the flutes 44 in the joint 42 arealready partly engaged between the flutes 57 in the bearing body 54,thereby ensuring guidance of the head of the inner core tube. The rib 37which rests upon the ramp 35 becomes aligned with and received withinthe groove 36 as soon as an angular motion of the shaft 47 creates atorque in the bearing 49-52 to rotate the body 54. As soon as the rib 37is received into the slot 36, the head of the inner core tube movesdownwardly under gravity forces engaging the coating 41 with the conicalseat 58 of the bearing body 54. From that moment on the inner core tubeis connected for joint angular motion with the stator or body of theturbo-coredrill and has a definite angular setting, i.e., is orientedwith respect to it. However the inner core tube remains free to be movedaxially with respect to the stator, and the axial position of the lowerend of said tube remains stable relative to the drilling tool. Thebearing body 54 and the discs 52 are held stationary by the inner coretube through the medium of the flutes 44 and 57.

Where, for example, owing to the size of the parts, the torquetransmitted between the shaft 47 and the head 38 of the inner core tubeis insuflicient for ensuring such an angular displacement of said headas to bring the rib 37 into registration with the slot 36, said torquecan be easily increased by interposing a resilient member between thepart of the hearing which is rigid with the shaft 47 and that one whichengages the flutes of the inner core tube, thereby 'bringing intocontact the oppositely located faces of the discs 52 and the seats 49,said faces having a sufficient coefficient of friction for ensuring apositive drive of the head on the ramp 35.

Minor constructional details may be varied without departing from thescope of the subjoined claims.

What is claimed is:

1. In a turbo-coredrill actuated by a circulating fluid and including atubular body portion, a stator part mounted in said body portion, ahollow shaft rotatably mounted within said body portion, rotor partfitted upon said hollow shaft, and a retractable inner core tube havinga fishing head and received within said hollow shaft and defining anannular space therewith, means associated with said head axiallypositioning said tube within said shaft; a sleeve-shaped sealing deviceinterposed between said inner core tube and the upper end of the hollowshaft for substantially obturating said annular space and forsubstantially preventing the flow of the circulating fluid through saidspace, first axial extending key means on said body portion, and secondaxial extending key means mounted on said tube for cooperative relationwith said first key means for angularly locking the inner core tube withrespect to said body portion.

2. In a turbo-coredrill actuated by a circulating fluid and including atubular body portion, a stator part mounted in said body portion, ahollow shaft rotatably mounted within said body portion, rotor partsmounted upon said hollow shaft, a retractable inner core tube having afishing head and received within said hollow shaft defining an annularspace therewith, a sleeve-shaped sealing device interposed between saidinner core tube and the upper end of said hollow shaft for substantiallyobturating said annular space and for substantially preventing fluidflow through said space, first bearing means at the upper end of saidhollow shaft, an outwardly directed shoulder portion carried by saidsleeve-shaped sealing device, second bearing means associated with saidshoulder portion, the second bearing means associated with the sealingdevice resting against the first bearing means associated with the shaftand permitting relative angular motion therebetween, inner flutesaxially formed on the sleeve-shaped sealing device, outer flutes axiallyformed on the upper end of the inner core tube and cooperating with saidinner flutes, a seat portion at the upper end of said sealing device,the head of the inner core tube sealingly engaging said seat portion,first key means rigidly associated with said body portion, and secondkey means formed on said head and cooperating with the first key meansfor holding said head against angular movement relative to said bodyportion.

3. In a turbo-coredn'll actuated by a circulating fluid and including atubular body portion, a stator part mounted in said body portion, ahollow shaft rotatably mounted within said body portion, rotor partsmounted upon said hollow shaft, a retractable inner core tube having afishing head affixed to the upper end thereof received within saidhollow shaft and defining an annular space therewith, a seat memberhaving a central bore afiixed to said body portion vertically above saidhollow shaft, said tube being lowered into said shaft through said seatmember bore and an abutment surface defined on said head engaging saidseat member to axially locate said tube within said shaft, axialextending channels defined in said seat member extending therethrough,an annular sleeve-shaped sealing device interposed between said tube andthe upper end of said shaft substantially obturating said annular spaceto substantially prevent the flow of circulatory fluid into said shaft,annular gaskets mounted in the bore of said sealing device sealinglyengaging said tube and permitting relative rotation between said sealingdevice and said tube, an annular seat defined on the upper end of saidshaft adjacent the bore thereof, a shoulderdefined on said sealingdevice sealingly engaging said annular seat upon said head engaging saidseat member, means defined on said tube engaging said sealing deviceupon withdrawing said tube from said shaft, withdrawing said sealingdevice from said shaft and passages defined in the wall of said tubelocated below said sealing device.

4. In a turbo-coredrill as in claim 3 wherein said sealing device isaxially positionable upon said core tube.

5. In a turbo-coredrill as in claim 2 wherein a guiding seat is mountedwithin said body portion and affixed thereto, said first key means beingdefined on said guiding seat, axial extending channels defined in saidguiding seat and extending therethrough, a bore defined in said guidingseat through which said core tube is inserted, an annular helicalsurface defined in said bore, the lower end of said helical surfaceintersecting said first key means, said second key means engaging saidhelical surface upon insertion of said tube into said shaft and engagingsaid first key means upon relative rotation of said tube in the shaftrotating direction.

6. In a turbo-coredn'll actuated by a circulating fluid and including atubular body portion, a stator part mounted within said body portion, ahollow shaft rotatably mounted within said body portion, rotor partsmounted upon said shaft, a retractable inner core tube having a fishinghead afiixed thereto received Within said shaft defining an annularspace therewith, a seat defined on said body portion above said shaft,said core tube head engaging said seat, circulation channels defined insaid seat, a sleeve-shaped sealing device interposed between said tubeand the upper end of said shaft substantially obtura'ting said annularspace and substantially preventing flow of the circulating fluid throughsaid space, said sealing device defining a small annular space with saidinner core tube, bearing means interposed between said sealing deviceand tube within said small annular space, a shoulder defined on saidsealing device engaging the upper end of said hollow shaft, and apassage defined in the wall of said tube below said sealing device.

7. In a tu-rbo-coredrill actuated by a circulating fluid and including atubular body portion, a stator part mounted in said body portion, ahollow shaft rotatably mounted within said body portion, rotor partsmounted upon said shaft, a retractable inner core tube having a fishinghead and received within said hollow shaft and defining an annular spacetherewith, a sleeve-shaped sealing device interposed between said innercore tube and the upper end of said hollow shaft for substantiallysealing off said annular space and for substantially preventing a flowof the circulating fluid through said space, an outwardly directedshoulder portion on said sealing device for abutment against the upperend of said hollow shaft, a seat portion in the upper end of saidsealing device, the head of the inner core tube resting against saidseat portion, firs-t key means affixed to said body portion, and secondkey means mounted on said fishing head engageable with said first keymeans for locking said tube against rotation relative to said bodyportion.

References Cited in the file of this patent UNITED STATES PATENTS Re.14,356 Stone Sept. 11, 1917 2,357,907 Phillips Sept. 12, 1944 2,862,691Cochran Dec. 2, 1958 2,890,859 Garrison June 16, 1959 2,910,273 Bon Oct.27, 1959 2,944,792 Gros July 12, 1960 OTHER REFERENCES Oil and GasJournal, Nov. 1955, page 99 relied on.

